JP3413851B2 - Optical scanning image information detection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of scanning a subject with a light beam and receiving reflected light from the subject.
The present invention relates to an apparatus for detecting a subject image, that is, an optical scanning image information detecting apparatus. 2. Description of the Related Art A subject image to which the present invention is applied is not only information relating to shading but also all information obtained by irradiating light. For example, physical and chemical information obtained from the absorption and scattering characteristics of the subject,
Information on distance and speed of the subject, measurement and recognition of three-dimensional structures, etc. Conventionally, as a scanner in the main scanning direction used for such two-dimensional scanning, a polygon mirror, a pyramidal mirror, a galvano mirror, a hologram and the like are known. Thus, when detecting weak scattered light from a subject image present in a wide-angle measurement range of 90 ° or more in a short-range area, a wide-angle scan and a wide aperture are required,
A polygon mirror and a pyramidal mirror are suitable, and a pyramidal mirror is superior in terms of compactness. FIG. 10 is an explanatory diagram of the function of a pyramidal mirror. In FIG. 10, 1 is a light source, 2 is a light beam, 3 is a pyramidal mirror, 4 is a rotation axis of the pyramidal mirror, 5 is a reflection surface of the pyramidal mirror, and 6 is a reflection surface of the light beam 2 when the pyramidal mirror 3 is rotated. The locus of the point of incidence on 5, and 7 is the reflected light beam. The light beam 2 emitted from the light source 1 travels in parallel with the rotation axis 4 of the pyramidal mirror 3 and
Incident on the reflection surface 5 of the light source. Pyramidal mirror 3 with rotation axis 4
, The locus 6 of the incident point of the light beam 2 on the reflecting surface 5 is known to draw a part of a conical curve as shown in FIG. Therefore, in general, the reflected light beam 7 performs not a linear scan but a curved scan. As described above, a pyramidal mirror which is optimal as a scanner in the main scanning direction used for two-dimensional scanning has a drawback that a reflected light beam performs a curved scanning. is there. Therefore, from two-dimensional scanning in combination with a sub-scanning mirror not shown,
When obtaining two-dimensional image information on a subject, there is a problem that image distortion occurs. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a light-scanning image information detecting device using a pyramidal mirror, which can efficiently use energy without reducing the intensity of a scanning light beam. The objective is to obtain two-dimensional image information having a wide angle of view, a compact size and no image distortion. An optical scanning image information detecting apparatus according to the present invention scans a subject with a light beam in a finite section having both ends, and receives reflected light from the subject to receive the light. the optical scanning image information detecting device for detecting an image has a reflecting surface of the multiple slopes, and Piramidarumira rotating the symmetry axis as the rotation axis, while rotating coaxially in synchronism with the rotation of the Piramidarumira, more By irradiating each of the light beams correspondingly to each reflection surface of the pyramidal mirror, an optical member that reflects the light beam at a fixed position on the reflection surface to make scanning light, and And a light-receiving element that receives, via the pyramidal mirror, reflected light from the subject to which each of the plurality of scanning lights is sequentially irradiated by scanning. are doing. FIG. 1 is a diagram for explaining the operation and principle of the optical scanning image information detecting apparatus according to the present invention. 1 to 7 are the same as those in FIG.
Although it is the same as 0, the pyramidal mirror 3 has a vertex cutout portion formed by cutting off the vertex. Reference numeral 9 denotes an optical member such as a prism that is fixed or fixed to the apex cutout of the pyramidal mirror 3 via a support plate 12, and guides the light beam 2 emitted from the light source 1 to a reflecting surface 5 for reflecting for light scanning. is there. Reference numerals 10 and 11 are opposing reflection surfaces of the prism 9. Note that, as described later, the presence of the apex resection is not an essential requirement. The light beam 2 emitted from the light source 1 travels along the rotation axis 4 of the pyramidal mirror 3 and enters the prism 9. Then, the light is reflected by the reflecting surfaces 10 and 11 of the prism 9, then goes out of the prism 9 and is reflected by the reflecting surface 5 on the slope of the pyramidal mirror 3. Prism 9
Since the light beam is fixed to the pyramidal mirror 3, the reflection position P of the light beam on the reflection surface 5 of the pyramidal mirror 3 is always at the same position irrespective of the rotation of the pyramidal mirror 3. With the rotation of, linear scanning is performed. Therefore, two-dimensional image information without image distortion can be obtained by two-dimensional scanning in combination with a sub-scanning mirror (not shown). FIGS. 2 to 5 are explanatory views of a first embodiment of the optical scanning image information detecting apparatus according to the present invention. 2 is a side view, FIG. 3 is a plan view, and FIGS. 4 and 5 are side views of a prism which is a part of the apparatus. 2 and 3,
Reference numerals 20 and 30 denote coupling prisms as optical coupling elements, reference numeral 40 denotes a separation prism as a light separation element, reference numeral 50 denotes a pyramidal mirror having a vertex cutout portion 51 formed by cutting off a vertex.
Numeral 2 denotes a cavity through which the rotating shaft 54 of the pyramidal mirror 50 passes concentrically, 53 denotes a bearing, 60 denotes a mirror, 70, 71
Is a lens, and 72 and 73 are light receiving elements. The coupling prisms 20 and 30 as the optical coupling elements and the separation prism 40 as the light separating element are optical path changing optical members as described in detail below. That is, these prisms are optical members that guide the light beam emitted from the light source to a reflecting surface that reflects the light beam for optical scanning. The details of the coupling prism 20 are shown in FIG. In FIG. 4, reference numerals 21 and 22 denote light beams, respectively, which are two laser semiconductor elements LD1 and L (not shown).
Emitted from D2, the polarization directions differ from each other by 90 °. That is, the light beam 21 is p-polarized light, and the light beam 22 is s-polarized light. 23 is a parallel prism, 24 is a triangular prism, 25 is a quarter-wave plate, 26 is a polarizing film, 23 'is a reflection surface of the parallel prism 23, and 80 is a light beam emitted from the coupling prism 20. The light beam 21 from the laser semiconductor element LD1 is incident on the parallel prism 23, reflected on the reflection surface 23 ', transmitted through the polarizing film 26 and the triangular prism 24,
The light is converted into circularly polarized light by the quarter-wave plate 25 and becomes an emission light beam 80. Similarly, the light beam 22 from the laser semiconductor element LD2 enters the triangular prism 24 and is reflected by the polarizing film 26. Subsequently, the light is converted into circularly polarized light by the quarter-wave plate 25, and becomes an emission light beam 80. The coupling prism 30 shown in FIG. 2 has the same function as the coupling prism 20 described above. That is,
Two laser semiconductor elements LD3 and LD4 not shown
Are emitted from the light source and two light beams having polarization directions different from each other by 90 °
0 '. The details of the separation prism 40 are shown in FIGS.
This is shown in FIG. FIG. 5B is a side view of FIG. 5A and 5B, reference numeral 41 denotes a quarter-wave plate, reference numerals 42 and 44 denote parallel prisms, reference numerals 43 and 45 denote triangular prisms, reference numeral 46 denotes a quarter-wave plate, reference numeral 47 denotes a polarizing film, and reference numeral 48 denotes a polarizing film.
Is the same polarizing film, but at a position rotated by 90 ° with respect to the polarizing film 47. The circularly polarized light beam 80 incident on the separation prism 40 from above is converted by the quarter-wave plate 41 into p-polarized light and s-polarized light. The p-polarized light passes through the polarizing film 47, is reflected by the polarizing film 48 rotated by 90 ° and the reflecting surface 44 ', and becomes a light beam 82 shown in FIG. 5B. The s-polarized light is reflected by the polarizing film 47 and the reflection surface 42 'to become a light beam 83. The circularly polarized light beam 80 'incident on the separating prism 40 from below is converted into p-polarized light and s-polarized light by the quarter-wave plate 46. p-polarized light is polarizing film 4
8. Light beam 85 is reflected by reflecting surface 45 '. The s-polarized light transmits through the polarizing film 48 and is rotated by 90 °.
7. The light is reflected by the reflecting surface 43 'to become a light beam 84 shown in FIG. From the above description, it can be seen that the circularly polarized light beams 80, 80 'incident from above and below the separation prism 40 eventually become four light beams 82, 83, 84, and 85. In FIG. 2 and FIG. 3, the separation prism 40 is fixed or fixed to the vertex cutout 51 of the pyramidal mirror 50. The pyramidal mirror 50 is provided with a cavity 52 in which a rotating shaft 54 passes through concentrically, and serves as a passage for light beams 80 and 80 '. Then, a bearing 53 for supporting the rotating shaft 54 is provided below the pyramidal mirror 50.
Are fixed or fixed, and the pyramidal mirror 50 is configured to be rotatable with respect to the rotation shaft 54 by a support mechanism and a drive mechanism (both not shown). As shown in FIGS. 5 (a), 5 (b) and 2, the light beams 83 and 84 are reflected by the reflecting surface 50 'of the pyramidal mirror 50, and are parallel to the paper surface. It becomes a light beam. Similarly, the light beams 82 and 85 are also reflected by the reflecting surface 50 'of the pyramidal mirror 50, and become horizontal light beams in a direction perpendicular to the paper surface. After all, the separation prism 40
The four light beams 82, 83, 84 and 85 emitted downward from are turned into four horizontal light beams. With the rotation of the pyramidal mirror 50 by a driving mechanism (not shown), these horizontal light beams are
The main scanning in the horizontal direction is performed. The mirror 60 performs a reciprocating rotational movement indicated by an arrow 62 around a rotation axis 61 by a driving mechanism (not shown), and the light beam 86 reflected by the mirror 60 scans in a sub-scanning direction perpendicular to the main scanning. I do. In practice, the light beam 86 performs main scanning in the horizontal direction.
Here, in order to simplify the drawing, the mirror 60 is shown rotated by 90 °. As apparent from the above description, the four light beams from the four laser semiconductor elements LD1, LD2, LD3 and LD4 correspond to four horizontal light beams, respectively. The four horizontal light beams are subjected to time-sequential amplitude modulation by a sine wave pulse shown in FIG. 6 or a rectangular wave pulse (not shown). In this case, 1 corresponds to the main scanning by the pyramidal mirror 50, respectively.
The modulation is applied only at the time interval of / 4 rotation. Of the scattered light from the subject (not shown), a signal component substantially parallel to the light beam 86 for two-dimensional scanning is reflected by the mirror 60, the reflecting surface 50 'of the pyramidal mirror 50, the lenses 70 and 71.
Are detected by light receiving elements 72 and 73 arranged on the axes of lenses 70 and 71, respectively (see FIG. 3). In the first embodiment, four semiconductor laser light sources are used in a detecting device including a pyramidal mirror 50 having four reflecting surfaces, coupling prisms 20, 30, a separating prism 40, a mirror 60, and the like. The horizontal light beam obtained in this way is time-sequentially modulated as shown in FIG. 6 to enable a two-dimensional scan with high speed and high energy use efficiency by a strong scanning light beam. Although shown, even when the number of semiconductor laser light sources or the number of reflecting surfaces of the pyramidal mirror is small, it can be easily changed. For example, when the number of reflecting surfaces of the pyramidal mirror is two, the separation prism may be partially changed as shown in FIG. In FIG. 7, reference numeral 91 denotes a quarter-wave plate, 96 and 97 are parallel prisms, 92 and 95 are triangular prisms, 94 is a half-wave plate, and 93 and 98 are polarizing films. Then, the circularly polarized light beam 80 incident on the partially changed separating prism 90 from above is separated by the quarter-wave plate 9.
1 converts it into p-polarized light and s-polarized light. The p-polarized light passes through the polarizing film 93, passes through the triangular prism 92, is converted into s-polarized light by the half-wave plate 94, is reflected by the polarizing film 98 and the reflection surface 96 ′ of the parallel prism 96, and becomes a light beam 84. . The s-polarized light converted by the quarter-wave plate 91 is reflected by the polarizing film 93 and the reflection surface 97 ′ to become a light beam 83. When the number of reflecting surfaces of the pyramidal mirror is two, the cavity 52 and the coupling prisms 20 and 30 are used.
(For example, the coupling prism 30) becomes unnecessary. 8A and 8B instead of the lenses 70 and 71.
1 lens 101, one light receiving element 102, or a Fresnel lens 103 equivalent to this,
02 can be used. In this case, the light receiving element 1
The number 02 may be provided on the rotating shaft 54, and there is an advantage that the loss of the signal light amount is smaller than the configuration in which the two lenses 70 and 71 are arranged. Further, the polarization separation by the polarizing film can be replaced with the polarization separation by a polarization beam splitter using calcite. FIGS. 9 (a), 9 (b) and 9 (c) are explanatory views of a light separating element in a reference example of the optical scanning image information detecting device. FIG. 9A shows a configuration and an optical path of the light separating element 109, and FIG. 9B is a side view of FIG. 9A. FIG.
In (a), 110 and 116 are quarter-wave plates, 1
11, 113 are parallel prisms, 112 is a polarizing film, 114
Is a triangular prism, 115 is a polarizing prism, 80, 80 '
Are light beams incident along the rotation axis 120, 82, 84
Is a horizontal light beam. 9B is a polarizing film, 83 and 85 are horizontal light beams, and 1 in FIG. 9C.
Reference numeral 18 denotes a polarizing film. The circularly polarized light beam 80 incident on the light separating element 109 from above is converted into p-polarized light and s-polarized light by the quarter-wave plate 110. The p-polarized light passes through the polarizing film 112 and the triangular prism 114, and is reflected by the polarizing film 117 of the polarizing prism 115 to become a horizontal light beam 83. Also,
The s-polarized light is the polarizing film 112 and the reflecting surface 1 of the parallel prism 111.
11 'and a horizontal light beam 8 reflected by the reflecting surface 111 "
It becomes 2. The circularly polarized light beam 80 ′ incident on the light separating element 109 from below is converted into p-polarized light and s-polarized light by the quarter-wave plate 116. p-polarized light is a polarizing prism 11
5 is reflected by the polarizing film 117 and becomes a horizontal light beam 85. The s-polarized light passes through the polarizing prism 115 and is reflected by the polarizing film 112 and the reflecting surfaces 113 'and 113 "of the parallel prism 113 to become a horizontal light beam 84. After all, the light separating element 109 is formed. Is the rotation center axis 1
Light beams 80, 80 'incident from above and below along 20
Is converted into four horizontal light beams 82, 83, 84 and 85. Thus, by rotating the light separating element 109 about the rotation center axis 120, it can be seen that scanning of a subject (not shown) is possible with four horizontal light beams orthogonal to each other. In the above case, the scattered light from the subject is detected by a light detection system (not shown) provided separately from the light separating element, for example, a light detection system using a pyramidal mirror described in the first embodiment. FIG. 9C shows that the light beams 80 and 80 ′ are
The light is converted into horizontal light beams 82 and 84 of a book, and its operation can be understood from the description of FIGS. 9A and 9B. Ginseng
It features considered example shows a case where the light separating element alone scanning is possible and that revealed that there is no need for integrally coupling the necessarily light separation element and Piramidarumira. In the first embodiment and the reference example described above ,
Regarding the deviation , a laser light source is used as a light source, and the light beams emitted from the light source are laser beams having polarization directions different from each other by 90 °, and light is separated according to the polarization direction. However, the light source and the light beam used in the optical scanning image information detecting device of the present invention are not limited to these. For example, a light beam emitted from a light source may be separated by a half mirror and used. In the first embodiment described above, the apex of the pyramidal mirror is cut off. This is a desirable configuration because it facilitates fixing of an optical member that guides a light beam from a light source to a reflection surface. However, in the optical scanning image information detection device of the present invention, it is sufficient that the light beam incident on the pyramidal mirror is rotatably provided in synchronization with the rotation of the pyramidal mirror. Is not a mandatory requirement. Further, fixing the optical member and the pyramidal mirror is a preferable mechanism for achieving the above-mentioned synchronization most simply. However, there is no problem even with a mechanism in which the optical member and the pyramidal mirror are separated and each has separate driving means, as long as the rotation periods are synchronized. As described above, the optical scanning image information detecting apparatus according to the present invention can efficiently utilize energy without reducing the intensity of the scanning light beam, and can realize a wide angle of view, a compact angle of view and no image distortion. Enables dimensional scanning.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view for explaining the operation and principle of the optical scanning image information detecting device of the present invention. FIG. 2 shows a first example of the optical scanning image information detecting device of the present invention.
It is a side view of an example. FIG. 3 is a diagram showing a first example of the optical scanning image information detecting device according to the present invention.
It is a top view of an example. FIG. 4 is a diagram illustrating the function of a coupling prism that is an optical path changing optical member according to the first embodiment. FIG. 5 is an explanatory diagram of functions of a separation prism which is an optical path changing optical member of the first embodiment. FIG. 6 is an explanatory diagram of modulation by a pulse of a horizontal light beam in the first embodiment. FIG. 7 is an explanatory diagram of a function of a separation prism partially changed in the optical member of the first embodiment. FIG. 8 is an explanatory diagram of an arrangement of a lens and a light receiving element which are components of the first embodiment. FIG. 9 is a functional explanatory diagram of a light separating element of a reference example in the light scanning image information detecting device. FIG. 10 is an explanatory diagram of a function of a pyramidal mirror. [Description of Signs] 1 Light source 2 Light beam 3 Pyramidal mirror 4 Rotation axis 5 Slope reflection surface of pyramidal mirror 9 Prism as optical path changing optical member

   ────────────────────────────────────────────────── ─── Continuation of front page       (56) References JP-A-57-204509 (JP, A)                 JP-A-55-113018 (JP, A)                 JP-A-51-98042 (JP, A)                 JP-A-54-158944 (JP, A)                 JP-A-1-320856 (JP, A)

Claims (1)

(57) [Claims 1] Optical scanning image information detection that scans a subject with a light beam for a finite section having both ends and receives reflected light from the subject to detect the subject image. The device has multiple reflective surfaces on a slope and rotates around a symmetry axis as a rotation axis.
And the coaxially rotating pyramidal mirror
Then, each of the plurality of light beams is
By irradiating correspondingly toward each reflecting surface,
Reflect the light beam at a fixed position on the reflecting surface
An optical member for forming scanning light, and each of the plurality of scanning lights is sequentially irradiated by the scanning.
The reflected light from the subject is
An optical scanning image information detecting device, comprising: a light receiving element that receives light through a light source.